1. Field of the Invention
The present invention relates to an information processing apparatus, method, and program. More particularly, the present invention relates to an information processing apparatus, method, and program able to reduce the standby power draw of an HDMI-CEC compatible device.
2. Description of the Related Art
HDMI (High-Definition Multimedia Interface) is becoming more prevalent as a digital interface for high-speed transmission of baseband signals containing a picture (i.e., video) signal as well as an audio signal accompanying the picture signal. The HDMI standard adds audio transmission functions and copyright protection functions to the DVI (Digital Visual Interface) standard for connecting personal computers (PCs) to displays, in an arrangement suitable for audio-visual (AV) equipment (see, for example, the High-Definition Multimedia Interface Specification Version 1.3a, Oct. 30, 2006).
An apparatus connected via HDMI (hereinafter referred to as an HDMI apparatus) may be one of three types: an HDMI source, an HDMI sink, or an HDMI repeater.
An HDMI source is provided with an output port for outputting audio and visual signals via HDMI. An HDMI sink is provided with an input port for accepting audio and visual signals as input via HDMI. An HDMI repeater is provided with one or more input ports and one or more output ports, and acts as both an HDMI source and an HDMI sink to function as a relay between the HDMI source and the HDMI sink.
HDMI includes TMDS (Transition Minimized Differential Signaling) channels, which are used as signal channels for unidirectionally transmitting baseband audio-visual signals from an HDMI source to an HDMI sink, via an HDMI repeater when appropriate. HDMI also has other channels, including a CEC (Consumer Electronics Control) line, which is used as a control channel for bidirectionally transmitting control signals (i.e., messages) used to control the HDMI source, the HDMI sink, and the HDMI repeater when appropriate.
In other words, in the physical layer, HDMI adopts the TMDS channels, with a CEC line being adopted for connecting the control systems of all apparatus connected by HDMI.
Furthermore, HDMI also adopts EDID (Extended Display Identification Data) for inter-device validation.
More specifically, HDMI adopts the VESA (Video Electronics Standards Association) DDC/EDID protocol for inter-device validation.
The DDC (Display Data Channel) is used by the HDMI source to read Enhanced EDID data from the HDMI sink as well as the HDMI repeater.
In other words, the HDMI sink and the HDMI repeater respectively include EDID ROM (Read-Only Memory) that stores EDID information related to that device's configuration and capability. Via the DDC, the HDMI source reads the EDID stored in the respective EDID ROM of the HDMI sink and the HDMI repeater, and on the basis of the EDID, recognizes the configuration and capability of the HDMI sink and the HDMI repeater.
Herein, an AV system will be considered wherein a television receiver (TV) acts as the HDMI sink, an AV amp acts as the HDMI repeater, and a BD (Blu-ray Disc™) recorder acts as the HDMI source.
Each HDMI apparatus constituting this AV system is CEC-compatible. Consequently, the operation of the apparatus are coordinated in accordance with user operations, such as playback operations in the BD recorder acting as the HDMI source, as well as power off or selection operations in the TV acting as the HDMI sink.
By means of an HDMI-TMDS signal transmitted via a TMDS channel (hereinafter also simply referred to as an HDMI signal), it is possible to transmit multi-channel PCM and similar signals that were unavailable for transmission using the optical digital output of the related art. As a result, the EDID of the AV amp is read by the BD recorder acting as the HDMI source, the AV amp receives an HDMI signal from the BD recorder, and only the picture signal contained in the HDMI signal is then transmitted to the TV. More specifically, the AV amp outputs an LPCM 7.1CH or similar high-quality audio signal received from the BD recorder, while additionally transmitting only the picture signal contained in the HDMI signal to the TV.
Moreover, if in a standby or similar mode, the AV amp is also able to transmit input signals to the TV, without the AV amp itself outputting audio. Since in this case the HDMI signal flows from the BD recorder to the AV amp, and then from the AV amp to the TV, the AV amp may simply transmit the HDMI signal received from the BD recorder to the TV as-is, for example. The AV amp thus performs what is referred to as an HDMI pass-through, causing the BD recorder to read the EDID of the TV, and then transmitting the HDMI signal received from the BD recorder to the TV as-is.